Such a gas-liquid separator is known from U.S. Pat. No. 4,361,469 and is also described in U.S. Pat. No. 5,695,548 and in Trans IChemE, vol. 77, Part A, October, pages 619–626. According to U.S. Pat. No. 4,361,469 the disclosed gas-liquid separator consists of a plurality of vertically spaced rows or levels of horizontally spaced parallel gutters. The individual gutters are each in the form of an elongate open top gutter of rectangular cross section having a bottom and side walls. The gutters are spaced apart vertically and horizontally. In use an up-flowing gas-liquid mixture having entrained liquid droplets carried thereby will vertically pass the rows of gutters. Because of the changes in flow direction, due to the particular gutter configuration, the gas-liquid mixture is thrust against the gutters, thereby separating the liquid droplets from the mixture. The liquid thereby falls into the open upper side of the gutters. Because the gutters are somewhat tilted the liquid will flow to the lower end of the gutter, at which point the liquid can be collected and transported to a lower level without being de-entrained by the upwardly moving gas and liquid.